Doesn't windows live work with steam games? I got the steam version of GTA 4 and it would sign me into windows live so I could see when my XBox friends were online. (Bonus XBox points for playing on PC. )

Never really used it much so can't say for quality, but I imagine Win Live would be for the XBoxers to stay in touch.
I'm a recovering WoW-a-holic so only know Team speak and Ventrilo.

Windows Live is not the same as Steam and Origin as far as I know. Steam and Origin are means of distributing software and games, Windows Live is just a hub you log into with a game.

I have games that I bought on Steam that log into Windows Live when I play them.

I have Steam and Origin on my PC, personally I prefer Steam as it has far more choice and diversity, Origin is primarily for EA games only.

You do not have to have Steam or Origin although there are some games that are specific to one or the other. I have Battlefield 3 through Origin but I never log into Origin to play it and you don't need to, Origin is just a way to sell the game it isn't required to Play.